//获取浏览器页面可见高度和宽度
var _PageHeight = document.documentElement.clientHeight,
    _PageWidth = document.documentElement.clientWidth;
//计算loading框距离顶部和左部的距离（loading框的宽度为215px，高度为61px）
var _LoadingTop = _PageHeight > 61 ? (_PageHeight - 61) / 2 : 0,
    _LoadingLeft = _PageWidth > 215 ? (_PageWidth - 215) / 2 : 0;
//在页面未加载完毕之前显示的loading Html自定义内容
var _LoadingHtml =
    '<div id="loadingDiv" ' +
    'style="position:absolute;font-size: 12px;left:0;width:100%;top:0;background:#f3f8ff;opacity:1;filter:alpha(opacity=80);z-index:10000;' +
    'height:' + _PageHeight + 'px;">' +
    '<div class="loadImg" ' +
    'style="position: absolute; cursor1: wait; width: auto; height: 57px; line-height: 57px;padding-left: 50px;'+
    'left: ' + _LoadingLeft + 'px;' + 'top:' + _LoadingTop + 'px; padding-right: 5px; ' +
    'border: none; color: #696969; ' +
    'background: #fff url(../../mobile/img/loadingImg.gif) no-repeat scroll 5px 10px;">' +
    '页面加载中，请等待...' +
    '</div>' +
    '</div>';
//css样式

//呈现loading效果
document.write(_LoadingHtml);
//监听加载状态改变
document.onreadystatechange = completeLoading;
//加载状态为complete时移除loading效果
function completeLoading() {
    setTimeout(function () {
        if (document.readyState == "complete") {
            var loadingMask = document.getElementById('loadingDiv');
            loadingMask.parentNode.removeChild(loadingMask);
        }
    },300);
}